Environmentally protected housings are used in a wide variety of applications, including containing and protecting electronic components of the type used for transferring signals over long distances. For example, the telecommunications industry transfers signals over optical fibers. If the signal is transferred over a long distance, the signal may be too weak by the time it reaches its destination to be useful. Consequently, electronic circuit cards are used to detect, clean up, and amplify a weak signal for retransmission through another length of fiber-optic cable. These electronic circuit cards are often deployed in environmentally protected housings located above and below ground.
Increased demands on the telecommunications industry, such as the advent of High-Bit-Rate Digital Subscriber Lines (HDSL), to meet the increasing needs of internet subscribers has resulted in the need to transfer more and stronger electrical signals over greater distances. One way of accomplishing this is to amplify the signals using electronic circuit cards deployed in environmentally protected housings. To meet the need for transferring stronger electrical signals over greater distances, electronic circuit cards having higher amplification capabilities, and thus greater heat dissipation rates, than the last generation of circuit cards of this type may be used. The need for more electrical signals of this type may be accommodated by placing as many of these higher-heat-dissipating circuit cards into a single environmentally protected housing as possible. However, existing housings configured to accommodate the heat loads of the last generation of electronic circuit cards cannot accommodate the increased heat load of larger numbers of higher-heat-dissipation electronic circuit cards.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for environmentally protected housings that can handle the increased heat load associated with increased numbers of higher-heat-dissipation electronic circuit cards and thereby maintain an acceptable operating temperature within the housing.